I put a 5" 3 shot group behind the shoulder of an antelope at 150 yards. Old style 95gr Nosler partitions. Thing just stood there for longer than he should have. Not a fan
And I had a buck I shot with 30-06 at 60 yards through the front of the heart that ran about 70 yards and left no blood trail I could follow. I just found the deer in a valley walking around looking. That was with a 150gr game king.
The kicker is I have had every single 243 deer myself and kids have shot preform better. They droped or didnt stumble as far and still left more blood.
That doesn't mean a 243 is a better deer round or a 30/06 is a bad round. I suspect I had bullet failure to expand on the 06 deer after looking at the wound track and lack of damage.
Animals have different reactions. A larger sample size and honest evaluation on bullet performance is how I go about things. But I still have a bias we all do.
In your case sounds like the bullets didnt transfer energy or expand properly in the thin skinned small animal. Balistuc tips or hitting some solid bone would have given you much different results I believe. About the same situation for me with my 06 deer example. Of course thats just my guess.
Nothing wrong with a single example making up your mind though. Honestly I did the same and got rid of the 06. Not that I think it was a bad gun I know its great I just had a poor preforming bullet/ wrong bullet choice on that one. My reason I dont need the extra recoil and powder to kill whitetails when a 243 and 7mm-08 flat do the job with less recoil and components.